Work on this program project will continue the investigation of developmental processes in the areas of socialization, cognitive development, and perceptual development. The socialization component includes both laboratory and observational studies of social behavior in mixed-age and same-age peer groups, studies of the role of social attributions in modifying children's social behavior during the preschool years, and studies dealing with the effects of adult leadership style on the manner in which children cope with tasks in situations involving both adults and peers. Studies of cooperation and competition will also be conducted. The studies of cognitive processes include a longitudinal study covering the first two years of life in which interrelations among intellectual and affective variables are studied along with the development of attachment to the mother in both normal children and Down's Syndrome children. Other studies focus on memory development for motor actions and language comprehension. In addition, the ecology of problem-solving is being examined and fine-grained analyses of the strategies used by young children in using tools are being conducted. How information about spatial orientation is employed by the young child is also being investigated. In the area of perceptual development a major concentration of work concerns perceptual-sensory capacities in infancy. The infant's behavior in response to cues for depth are being scrutinized, and the nature of the infant's visual information processing is also being examined. In studies of older children, the effects of auditory feedback on speech production are receiving attention, in addition to the manner in which music is processed. Children's responses to redundancies in perceptual information will also be studied, as will basic perceptual processes characterizing the pre-reading child. BIBLIOGRAPHIC REFERENCES: Hartup, W.W. Adolescent peer relations: A look to the future. In J.P. Hill & F. J. Monks (Eds.), Adolescence and youth in prospect. Guildford, England: IPC Science and Technology Press, 1977. Hartup, W.W. Peer relations: developmental implications and interaction in same- and mixed-age situations. Young Children, 1977, 32, 4-13, in press.